Validate component properties #264

.circleci/config.yml

@@ -49,6 +49,7 @@ jobs:
  python --version
  python -m unittest tests.development.test_base_component
  python -m unittest tests.development.test_component_loader
+ python -m unittest tests.development.test_component_validation
  python -m unittest tests.test_integration
  python -m unittest tests.test_resources
  python -m unittest tests.test_configs

.circleci/requirements/dev-requirements-py37.txt

@@ -9,8 +9,11 @@ mock
 tox
 tox-pyenv
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==2.1.1
 astroid==2.0.4
+Cerberus==1.2

.circleci/requirements/dev-requirements.txt

@@ -10,7 +10,10 @@ tox
 tox-pyenv
 mock
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==1.9.2
+Cerberus==1.2

.pylintrc37

@@ -63,6 +63,7 @@ confidence=
 disable=invalid-name,
  missing-docstring,
  print-statement,
+ too-many-lines,
  parameter-unpacking,
  unpacking-in-except,
  old-raise-syntax,

dash/dash.py

@@ -5,11 +5,13 @@
 import collections
 import importlib
 import json
+import pprint
 import pkgutil
 import warnings
 import re
 
 from functools import wraps
+from textwrap import dedent
 
 import plotly
 import dash_renderer
@@ -20,6 +22,8 @@
 from .dependencies import Event, Input, Output, State
 from .resources import Scripts, Css
 from .development.base_component import Component
+from .development.validator import (DashValidator,
+ generate_validation_error_message)
 from . import exceptions
 from ._utils import AttributeDict as _AttributeDict
 from ._utils import interpolate_str as _interpolate
@@ -84,6 +88,7 @@ def __init__(
  external_scripts=None,
  external_stylesheets=None,
  suppress_callback_exceptions=None,
+ suppress_validation_exceptions=None,
  components_cache_max_age=None,
  **kwargs):
 
@@ -126,6 +131,10 @@ def __init__(
  'suppress_callback_exceptions',
  suppress_callback_exceptions, env_configs, False
  ),
+ 'suppress_validation_exceptions': _configs.get_config(
+ 'suppress_validation_exceptions',
+ suppress_validation_exceptions, env_configs, False
+ ),
  'routes_pathname_prefix': routes_pathname_prefix,
  'requests_pathname_prefix': requests_pathname_prefix,
  'include_assets_files': _configs.get_config(
@@ -168,6 +177,7 @@ def _handle_error(error):
  self.assets_ignore = assets_ignore
 
  self.registered_paths = {}
+ self.namespaces = {}
 
  # urls
  self.routes = []
@@ -256,7 +266,6 @@ def layout(self, value):
  'a dash component.')
 
  self._layout = value
-
  layout_value = self._layout_value()
  # pylint: disable=protected-access
  self.css._update_layout(layout_value)
@@ -575,7 +584,7 @@ def react(self, *args, **kwargs):
  'Use `callback` instead. `callback` has a new syntax too, '
  'so make sure to call `help(app.callback)` to learn more.')
 
- def _validate_callback(self, output, inputs, state, events):
+ def _validate_callback_definition(self, output, inputs, state, events):
  # pylint: disable=too-many-branches
  layout = self._cached_layout or self._layout_value()
 
@@ -713,7 +722,7 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
- def _validate_callback_output(self, output_value, output):
+ def _debug_callback_serialization_error(self, output_value, output):
  valid = [str, dict, int, float, type(None), Component]
 
  def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
@@ -831,7 +840,7 @@ def _validate_value(val, index=None):
  # relationships
  # pylint: disable=dangerous-default-value
  def callback(self, output, inputs=[], state=[], events=[]):
- self._validate_callback(output, inputs, state, events)
+ self._validate_callback_definition(output, inputs, state, events)
 
  callback_id = '{}.{}'.format(
  output.component_id, output.component_property
@@ -853,13 +862,11 @@ def callback(self, output, inputs=[], state=[], events=[]):
 
  def wrap_func(func):
  @wraps(func)
- def add_context(*args, **kwargs):
-
- output_value = func(*args, **kwargs)
+ def add_context(validated_output):
  response = {
  'response': {
  'props': {
- output.component_property: output_value
+ output.component_property: validated_output
  }
  }
  }
@@ -870,7 +877,10 @@ def add_context(*args, **kwargs):
  cls=plotly.utils.PlotlyJSONEncoder
  )
  except TypeError:
- self._validate_callback_output(output_value, output)
+ self._debug_callback_serialization_error(
+ validated_output,
+ output
+ )
  raise exceptions.InvalidCallbackReturnValue('''
  The callback for property `{property:s}`
  of component `{id:s}` returned a value
@@ -887,6 +897,7 @@ def add_context(*args, **kwargs):
  mimetype='application/json'
  )
 
+ self.callback_map[callback_id]['func'] = func
  self.callback_map[callback_id]['callback'] = add_context
 
  return add_context
@@ -915,7 +926,88 @@ def dispatch(self):
  c['id'] == component_registration['id']
  ][0])
 
- return self.callback_map[target_id]['callback'](*args)
+ output_value = self.callback_map[target_id]['func'](*args)
+
+ # Only validate if we get required information from renderer
+ # and validation is not turned off by user
+ if (
+ (not self.config.suppress_validation_exceptions) and
+ 'namespace' in output and
+ 'type' in output
+ ):
+ # Python2.7 might make these keys and values unicode
+ namespace = str(output['namespace'])
+ component_type = str(output['type'])
+ component_id = str(output['id'])
+ component_property = str(output['property'])
+ callback_func_name = self.callback_map[target_id]['func'].__name__
+ self._validate_callback_output(namespace, component_type,
+ component_id, component_property,
+ callback_func_name,
+ args, output_value)
+
+ return self.callback_map[target_id]['callback'](output_value)
+
+ def _validate_callback_output(self, namespace, component_type,
+ component_id, component_property,
+ callback_func_name, args, value):
+ module = sys.modules[namespace]
+ component = getattr(module, component_type)
+ # pylint: disable=protected-access
+ validator = DashValidator({
+ component_property: component._schema.get(component_property, {})
+ })
+ valid = validator.validate({component_property: value})
+ if not valid:
+ error_message = dedent("""\
+
+ A Dash Callback produced an invalid value!
+
+ Dash tried to update the `{component_property}` prop of the
+ `{component_name}` with id `{component_id}` by calling the
+ `{callback_func_name}` function with `{args}` as arguments.
+
+ This function call returned `{value}`, which did not pass
+ validation tests for the `{component_name}` component.
+
+ The expected schema for the `{component_property}` prop of the
+ `{component_name}` component is:
+
+ ***************************************************************
+ {component_schema}
+ ***************************************************************
+
+ The errors in validation are as follows:
+
+ """).format(
+ component_property=component_property,
+ component_name=component.__name__,
+ component_id=component_id,
+ callback_func_name=callback_func_name,
+ args='({})'.format(", ".join(map(repr, args))),
+ value=value,
+ component_schema=pprint.pformat(
+ component._schema[component_property]
+ )
+ )
+
+ error_message = generate_validation_error_message(
+ validator.errors,
+ 0,
+ error_message
+ ) + dedent("""
+ You can turn off these validation exceptions by setting
+ `app.config.suppress_validation_exceptions=True`
+ """)
+
+ raise exceptions.CallbackOutputValidationError(error_message)
+ # Must also validate initialization of newly created components
+ if component_property == 'children':
+ if isinstance(value, Component):
+ value.validate()
+ for component in value.traverse():
+ if isinstance(component, Component):
+ component.validate()
 
  def _validate_layout(self):
  if self.layout is None:
@@ -932,6 +1024,11 @@ def _validate_layout(self):
 
  component_ids = {layout_id} if layout_id else set()
  for component in to_validate.traverse():
+ if (
+ not self.config.suppress_validation_exceptions and
+ isinstance(component, Component)
+ ):
+ component.validate()
  component_id = getattr(component, 'id', None)
  if component_id and component_id in component_ids:
  raise exceptions.DuplicateIdError(
@@ -1057,5 +1154,9 @@ def run_server(self,
  :return:
  """
  debug = self.enable_dev_tools(debug, dev_tools_serve_dev_bundles)
+ if not debug:
+ # Do not throw debugging exceptions in production.
+ self.config.suppress_validation_exceptions = True
+ self.config.suppress_callback_exceptions = True
  self.server.run(port=port, debug=debug,
  **flask_run_options)

.circleci/config.yml

@@ -49,6 +49,7 @@ jobs:
  python --version
  python -m unittest tests.development.test_base_component
  python -m unittest tests.development.test_component_loader
+ python -m unittest tests.development.test_component_validation
  python -m unittest tests.test_integration
  python -m unittest tests.test_resources
  python -m unittest tests.test_configs

.circleci/requirements/dev-requirements-py37.txt

@@ -9,8 +9,11 @@ mock
 tox
 tox-pyenv
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==2.1.1
 astroid==2.0.4
+Cerberus==1.2

.circleci/requirements/dev-requirements.txt

@@ -10,7 +10,10 @@ tox
 tox-pyenv
 mock
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==1.9.2
+Cerberus==1.2

.pylintrc37

@@ -63,6 +63,7 @@ confidence=
 disable=invalid-name,
  missing-docstring,
  print-statement,
+ too-many-lines,
  parameter-unpacking,
  unpacking-in-except,
  old-raise-syntax,

dash/dash.py

@@ -5,11 +5,13 @@
 import collections
 import importlib
 import json
+import pprint
 import pkgutil
 import warnings
 import re
 
 from functools import wraps
+from textwrap import dedent
 
 import plotly
 import dash_renderer
@@ -20,6 +22,8 @@
 from .dependencies import Event, Input, Output, State
 from .resources import Scripts, Css
 from .development.base_component import Component
+from .development.validator import (DashValidator,
+ generate_validation_error_message)
 from . import exceptions
 from ._utils import AttributeDict as _AttributeDict
 from ._utils import interpolate_str as _interpolate
@@ -84,6 +88,7 @@ def __init__(
  external_scripts=None,
  external_stylesheets=None,
  suppress_callback_exceptions=None,
+ suppress_validation_exceptions=None,
  components_cache_max_age=None,
  **kwargs):
 
@@ -126,6 +131,10 @@ def __init__(
  'suppress_callback_exceptions',
  suppress_callback_exceptions, env_configs, False
  ),
+ 'suppress_validation_exceptions': _configs.get_config(
+ 'suppress_validation_exceptions',
+ suppress_validation_exceptions, env_configs, False
+ ),
  'routes_pathname_prefix': routes_pathname_prefix,
  'requests_pathname_prefix': requests_pathname_prefix,
  'include_assets_files': _configs.get_config(
@@ -168,6 +177,7 @@ def _handle_error(error):
  self.assets_ignore = assets_ignore
 
  self.registered_paths = {}
+ self.namespaces = {}
 
  # urls
  self.routes = []
@@ -256,7 +266,6 @@ def layout(self, value):
  'a dash component.')
 
  self._layout = value
-
  layout_value = self._layout_value()
  # pylint: disable=protected-access
  self.css._update_layout(layout_value)
@@ -575,7 +584,7 @@ def react(self, *args, **kwargs):
  'Use `callback` instead. `callback` has a new syntax too, '
  'so make sure to call `help(app.callback)` to learn more.')
 
- def _validate_callback(self, output, inputs, state, events):
+ def _validate_callback_definition(self, output, inputs, state, events):
  # pylint: disable=too-many-branches
  layout = self._cached_layout or self._layout_value()
 
@@ -713,7 +722,7 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
- def _validate_callback_output(self, output_value, output):
+ def _debug_callback_serialization_error(self, output_value, output):
  valid = [str, dict, int, float, type(None), Component]
 
  def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
@@ -831,7 +840,7 @@ def _validate_value(val, index=None):
  # relationships
  # pylint: disable=dangerous-default-value
  def callback(self, output, inputs=[], state=[], events=[]):
- self._validate_callback(output, inputs, state, events)
+ self._validate_callback_definition(output, inputs, state, events)
 
  callback_id = '{}.{}'.format(
  output.component_id, output.component_property
@@ -853,13 +862,11 @@ def callback(self, output, inputs=[], state=[], events=[]):
 
  def wrap_func(func):
  @wraps(func)
- def add_context(*args, **kwargs):
-
- output_value = func(*args, **kwargs)
+ def add_context(validated_output):
  response = {
  'response': {
  'props': {
- output.component_property: output_value
+ output.component_property: validated_output
  }
  }
  }
@@ -870,7 +877,10 @@ def add_context(*args, **kwargs):
  cls=plotly.utils.PlotlyJSONEncoder
  )
  except TypeError:
- self._validate_callback_output(output_value, output)
+ self._debug_callback_serialization_error(
+ validated_output,
+ output
+ )
  raise exceptions.InvalidCallbackReturnValue('''
  The callback for property `{property:s}`
  of component `{id:s}` returned a value
@@ -887,6 +897,7 @@ def add_context(*args, **kwargs):
  mimetype='application/json'
  )
 
+ self.callback_map[callback_id]['func'] = func
  self.callback_map[callback_id]['callback'] = add_context
 
  return add_context
@@ -915,7 +926,88 @@ def dispatch(self):
  c['id'] == component_registration['id']
  ][0])
 
- return self.callback_map[target_id]['callback'](*args)
+ output_value = self.callback_map[target_id]['func'](*args)
+
+ # Only validate if we get required information from renderer
+ # and validation is not turned off by user
+ if (
+ (not self.config.suppress_validation_exceptions) and
+ 'namespace' in output and
+ 'type' in output
+ ):
+ # Python2.7 might make these keys and values unicode
+ namespace = str(output['namespace'])
+ component_type = str(output['type'])
+ component_id = str(output['id'])
+ component_property = str(output['property'])
+ callback_func_name = self.callback_map[target_id]['func'].__name__
+ self._validate_callback_output(namespace, component_type,
+ component_id, component_property,
+ callback_func_name,
+ args, output_value)
+
+ return self.callback_map[target_id]['callback'](output_value)
+
+ def _validate_callback_output(self, namespace, component_type,
+ component_id, component_property,
+ callback_func_name, args, value):
+ module = sys.modules[namespace]
+ component = getattr(module, component_type)
+ # pylint: disable=protected-access
+ validator = DashValidator({
+ component_property: component._schema.get(component_property, {})
+ })
+ valid = validator.validate({component_property: value})
+ if not valid:
+ error_message = dedent("""\
+
+ A Dash Callback produced an invalid value!
+
+ Dash tried to update the `{component_property}` prop of the
+ `{component_name}` with id `{component_id}` by calling the
+ `{callback_func_name}` function with `{args}` as arguments.
+
+ This function call returned `{value}`, which did not pass
+ validation tests for the `{component_name}` component.
+
+ The expected schema for the `{component_property}` prop of the
+ `{component_name}` component is:
+
+ ***************************************************************
+ {component_schema}
+ ***************************************************************
+
+ The errors in validation are as follows:
+
+ """).format(
+ component_property=component_property,
+ component_name=component.__name__,
+ component_id=component_id,
+ callback_func_name=callback_func_name,
+ args='({})'.format(", ".join(map(repr, args))),
+ value=value,
+ component_schema=pprint.pformat(
+ component._schema[component_property]
+ )
+ )
+
+ error_message = generate_validation_error_message(
+ validator.errors,
+ 0,
+ error_message
+ ) + dedent("""
+ You can turn off these validation exceptions by setting
+ `app.config.suppress_validation_exceptions=True`
+ """)
+
+ raise exceptions.CallbackOutputValidationError(error_message)
+ # Must also validate initialization of newly created components
+ if component_property == 'children':
+ if isinstance(value, Component):
+ value.validate()
+ for component in value.traverse():
+ if isinstance(component, Component):
+ component.validate()
 
  def _validate_layout(self):
  if self.layout is None:
@@ -932,6 +1024,11 @@ def _validate_layout(self):
 
  component_ids = {layout_id} if layout_id else set()
  for component in to_validate.traverse():
+ if (
+ not self.config.suppress_validation_exceptions and
+ isinstance(component, Component)
+ ):
+ component.validate()
  component_id = getattr(component, 'id', None)
  if component_id and component_id in component_ids:
  raise exceptions.DuplicateIdError(
@@ -1057,5 +1154,9 @@ def run_server(self,
  :return:
  """
  debug = self.enable_dev_tools(debug, dev_tools_serve_dev_bundles)
+ if not debug:
+ # Do not throw debugging exceptions in production.
+ self.config.suppress_validation_exceptions = True
+ self.config.suppress_callback_exceptions = True
  self.server.run(port=port, debug=debug,
  **flask_run_options)

.circleci/config.yml

@@ -49,6 +49,7 @@ jobs:
  python --version
  python -m unittest tests.development.test_base_component
  python -m unittest tests.development.test_component_loader
+ python -m unittest tests.development.test_component_validation
  python -m unittest tests.test_integration
  python -m unittest tests.test_resources
  python -m unittest tests.test_configs

.circleci/requirements/dev-requirements-py37.txt

@@ -9,8 +9,11 @@ mock
 tox
 tox-pyenv
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==2.1.1
 astroid==2.0.4
+Cerberus==1.2

.circleci/requirements/dev-requirements.txt

@@ -10,7 +10,10 @@ tox
 tox-pyenv
 mock
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==1.9.2
+Cerberus==1.2

.pylintrc37

@@ -63,6 +63,7 @@ confidence=
 disable=invalid-name,
  missing-docstring,
  print-statement,
+ too-many-lines,
  parameter-unpacking,
  unpacking-in-except,
  old-raise-syntax,

dash/dash.py

@@ -5,11 +5,13 @@
 import collections
 import importlib
 import json
+import pprint
 import pkgutil
 import warnings
 import re
 
 from functools import wraps
+from textwrap import dedent
 
 import plotly
 import dash_renderer
@@ -20,6 +22,8 @@
 from .dependencies import Event, Input, Output, State
 from .resources import Scripts, Css
 from .development.base_component import Component
+from .development.validator import (DashValidator,
+ generate_validation_error_message)
 from . import exceptions
 from ._utils import AttributeDict as _AttributeDict
 from ._utils import interpolate_str as _interpolate
@@ -84,6 +88,7 @@ def __init__(
  external_scripts=None,
  external_stylesheets=None,
  suppress_callback_exceptions=None,
+ suppress_validation_exceptions=None,
  components_cache_max_age=None,
  **kwargs):
 
@@ -126,6 +131,10 @@ def __init__(
  'suppress_callback_exceptions',
  suppress_callback_exceptions, env_configs, False
  ),
+ 'suppress_validation_exceptions': _configs.get_config(
+ 'suppress_validation_exceptions',
+ suppress_validation_exceptions, env_configs, False
+ ),
  'routes_pathname_prefix': routes_pathname_prefix,
  'requests_pathname_prefix': requests_pathname_prefix,
  'include_assets_files': _configs.get_config(
@@ -168,6 +177,7 @@ def _handle_error(error):
  self.assets_ignore = assets_ignore
 
  self.registered_paths = {}
+ self.namespaces = {}
 
  # urls
  self.routes = []
@@ -256,7 +266,6 @@ def layout(self, value):
  'a dash component.')
 
  self._layout = value
-
  layout_value = self._layout_value()
  # pylint: disable=protected-access
  self.css._update_layout(layout_value)
@@ -575,7 +584,7 @@ def react(self, *args, **kwargs):
  'Use `callback` instead. `callback` has a new syntax too, '
  'so make sure to call `help(app.callback)` to learn more.')
 
- def _validate_callback(self, output, inputs, state, events):
+ def _validate_callback_definition(self, output, inputs, state, events):
  # pylint: disable=too-many-branches
  layout = self._cached_layout or self._layout_value()
 
@@ -713,7 +722,7 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
- def _validate_callback_output(self, output_value, output):
+ def _debug_callback_serialization_error(self, output_value, output):
  valid = [str, dict, int, float, type(None), Component]
 
  def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
@@ -831,7 +840,7 @@ def _validate_value(val, index=None):
  # relationships
  # pylint: disable=dangerous-default-value
  def callback(self, output, inputs=[], state=[], events=[]):
- self._validate_callback(output, inputs, state, events)
+ self._validate_callback_definition(output, inputs, state, events)
 
  callback_id = '{}.{}'.format(
  output.component_id, output.component_property
@@ -853,13 +862,11 @@ def callback(self, output, inputs=[], state=[], events=[]):
 
  def wrap_func(func):
  @wraps(func)
- def add_context(*args, **kwargs):
-
- output_value = func(*args, **kwargs)
+ def add_context(validated_output):
  response = {
  'response': {
  'props': {
- output.component_property: output_value
+ output.component_property: validated_output
  }
  }
  }
@@ -870,7 +877,10 @@ def add_context(*args, **kwargs):
  cls=plotly.utils.PlotlyJSONEncoder
  )
  except TypeError:
- self._validate_callback_output(output_value, output)
+ self._debug_callback_serialization_error(
+ validated_output,
+ output
+ )
  raise exceptions.InvalidCallbackReturnValue('''
  The callback for property `{property:s}`
  of component `{id:s}` returned a value
@@ -887,6 +897,7 @@ def add_context(*args, **kwargs):
  mimetype='application/json'
  )
 
+ self.callback_map[callback_id]['func'] = func
  self.callback_map[callback_id]['callback'] = add_context
 
  return add_context
@@ -915,7 +926,88 @@ def dispatch(self):
  c['id'] == component_registration['id']
  ][0])
 
- return self.callback_map[target_id]['callback'](*args)
+ output_value = self.callback_map[target_id]['func'](*args)
+
+ # Only validate if we get required information from renderer
+ # and validation is not turned off by user
+ if (
+ (not self.config.suppress_validation_exceptions) and
+ 'namespace' in output and
+ 'type' in output
+ ):
+ # Python2.7 might make these keys and values unicode
+ namespace = str(output['namespace'])
+ component_type = str(output['type'])
+ component_id = str(output['id'])
+ component_property = str(output['property'])
+ callback_func_name = self.callback_map[target_id]['func'].__name__
+ self._validate_callback_output(namespace, component_type,
+ component_id, component_property,
+ callback_func_name,
+ args, output_value)
+
+ return self.callback_map[target_id]['callback'](output_value)
+
+ def _validate_callback_output(self, namespace, component_type,
+ component_id, component_property,
+ callback_func_name, args, value):
+ module = sys.modules[namespace]
+ component = getattr(module, component_type)
+ # pylint: disable=protected-access
+ validator = DashValidator({
+ component_property: component._schema.get(component_property, {})
+ })
+ valid = validator.validate({component_property: value})
+ if not valid:
+ error_message = dedent("""\
+
+ A Dash Callback produced an invalid value!
+
+ Dash tried to update the `{component_property}` prop of the
+ `{component_name}` with id `{component_id}` by calling the
+ `{callback_func_name}` function with `{args}` as arguments.
+
+ This function call returned `{value}`, which did not pass
+ validation tests for the `{component_name}` component.
+
+ The expected schema for the `{component_property}` prop of the
+ `{component_name}` component is:
+
+ ***************************************************************
+ {component_schema}
+ ***************************************************************
+
+ The errors in validation are as follows:
+
+ """).format(
+ component_property=component_property,
+ component_name=component.__name__,
+ component_id=component_id,
+ callback_func_name=callback_func_name,
+ args='({})'.format(", ".join(map(repr, args))),
+ value=value,
+ component_schema=pprint.pformat(
+ component._schema[component_property]
+ )
+ )
+
+ error_message = generate_validation_error_message(
+ validator.errors,
+ 0,
+ error_message
+ ) + dedent("""
+ You can turn off these validation exceptions by setting
+ `app.config.suppress_validation_exceptions=True`
+ """)
+
+ raise exceptions.CallbackOutputValidationError(error_message)
+ # Must also validate initialization of newly created components
+ if component_property == 'children':
+ if isinstance(value, Component):
+ value.validate()
+ for component in value.traverse():
+ if isinstance(component, Component):
+ component.validate()
 
  def _validate_layout(self):
  if self.layout is None:
@@ -932,6 +1024,11 @@ def _validate_layout(self):
 
  component_ids = {layout_id} if layout_id else set()
  for component in to_validate.traverse():
+ if (
+ not self.config.suppress_validation_exceptions and
+ isinstance(component, Component)
+ ):
+ component.validate()
  component_id = getattr(component, 'id', None)
  if component_id and component_id in component_ids:
  raise exceptions.DuplicateIdError(
@@ -1057,5 +1154,9 @@ def run_server(self,
  :return:
  """
  debug = self.enable_dev_tools(debug, dev_tools_serve_dev_bundles)
+ if not debug:
+ # Do not throw debugging exceptions in production.
+ self.config.suppress_validation_exceptions = True
+ self.config.suppress_callback_exceptions = True
  self.server.run(port=port, debug=debug,
  **flask_run_options)

.circleci/config.yml

@@ -49,6 +49,7 @@ jobs:
  python --version
  python -m unittest tests.development.test_base_component
  python -m unittest tests.development.test_component_loader
+ python -m unittest tests.development.test_component_validation
  python -m unittest tests.test_integration
  python -m unittest tests.test_resources
  python -m unittest tests.test_configs

.circleci/requirements/dev-requirements-py37.txt

@@ -9,8 +9,11 @@ mock
 tox
 tox-pyenv
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==2.1.1
 astroid==2.0.4
+Cerberus==1.2

.circleci/requirements/dev-requirements.txt

@@ -10,7 +10,10 @@ tox
 tox-pyenv
 mock
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==1.9.2
+Cerberus==1.2

.pylintrc37

@@ -63,6 +63,7 @@ confidence=
 disable=invalid-name,
  missing-docstring,
  print-statement,
+ too-many-lines,
  parameter-unpacking,
  unpacking-in-except,
  old-raise-syntax,

dash/dash.py

@@ -5,11 +5,13 @@
 import collections
 import importlib
 import json
+import pprint
 import pkgutil
 import warnings
 import re
 
 from functools import wraps
+from textwrap import dedent
 
 import plotly
 import dash_renderer
@@ -20,6 +22,8 @@
 from .dependencies import Event, Input, Output, State
 from .resources import Scripts, Css
 from .development.base_component import Component
+from .development.validator import (DashValidator,
+ generate_validation_error_message)
 from . import exceptions
 from ._utils import AttributeDict as _AttributeDict
 from ._utils import interpolate_str as _interpolate
@@ -84,6 +88,7 @@ def __init__(
  external_scripts=None,
  external_stylesheets=None,
  suppress_callback_exceptions=None,
+ suppress_validation_exceptions=None,
  components_cache_max_age=None,
  **kwargs):
 
@@ -126,6 +131,10 @@ def __init__(
  'suppress_callback_exceptions',
  suppress_callback_exceptions, env_configs, False
  ),
+ 'suppress_validation_exceptions': _configs.get_config(
+ 'suppress_validation_exceptions',
+ suppress_validation_exceptions, env_configs, False
+ ),
  'routes_pathname_prefix': routes_pathname_prefix,
  'requests_pathname_prefix': requests_pathname_prefix,
  'include_assets_files': _configs.get_config(
@@ -168,6 +177,7 @@ def _handle_error(error):
  self.assets_ignore = assets_ignore
 
  self.registered_paths = {}
+ self.namespaces = {}
 
  # urls
  self.routes = []
@@ -256,7 +266,6 @@ def layout(self, value):
  'a dash component.')
 
  self._layout = value
-
  layout_value = self._layout_value()
  # pylint: disable=protected-access
  self.css._update_layout(layout_value)
@@ -575,7 +584,7 @@ def react(self, *args, **kwargs):
  'Use `callback` instead. `callback` has a new syntax too, '
  'so make sure to call `help(app.callback)` to learn more.')
 
- def _validate_callback(self, output, inputs, state, events):
+ def _validate_callback_definition(self, output, inputs, state, events):
  # pylint: disable=too-many-branches
  layout = self._cached_layout or self._layout_value()
 
@@ -713,7 +722,7 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
- def _validate_callback_output(self, output_value, output):
+ def _debug_callback_serialization_error(self, output_value, output):
  valid = [str, dict, int, float, type(None), Component]
 
  def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
@@ -831,7 +840,7 @@ def _validate_value(val, index=None):
  # relationships
  # pylint: disable=dangerous-default-value
  def callback(self, output, inputs=[], state=[], events=[]):
- self._validate_callback(output, inputs, state, events)
+ self._validate_callback_definition(output, inputs, state, events)
 
  callback_id = '{}.{}'.format(
  output.component_id, output.component_property
@@ -853,13 +862,11 @@ def callback(self, output, inputs=[], state=[], events=[]):
 
  def wrap_func(func):
  @wraps(func)
- def add_context(*args, **kwargs):
-
- output_value = func(*args, **kwargs)
+ def add_context(validated_output):
  response = {
  'response': {
  'props': {
- output.component_property: output_value
+ output.component_property: validated_output
  }
  }
  }
@@ -870,7 +877,10 @@ def add_context(*args, **kwargs):
  cls=plotly.utils.PlotlyJSONEncoder
  )
  except TypeError:
- self._validate_callback_output(output_value, output)
+ self._debug_callback_serialization_error(
+ validated_output,
+ output
+ )
  raise exceptions.InvalidCallbackReturnValue('''
  The callback for property `{property:s}`
  of component `{id:s}` returned a value
@@ -887,6 +897,7 @@ def add_context(*args, **kwargs):
  mimetype='application/json'
  )
 
+ self.callback_map[callback_id]['func'] = func
  self.callback_map[callback_id]['callback'] = add_context
 
  return add_context
@@ -915,7 +926,88 @@ def dispatch(self):
  c['id'] == component_registration['id']
  ][0])
 
- return self.callback_map[target_id]['callback'](*args)
+ output_value = self.callback_map[target_id]['func'](*args)
+
+ # Only validate if we get required information from renderer
+ # and validation is not turned off by user
+ if (
+ (not self.config.suppress_validation_exceptions) and
+ 'namespace' in output and
+ 'type' in output
+ ):
+ # Python2.7 might make these keys and values unicode
+ namespace = str(output['namespace'])
+ component_type = str(output['type'])
+ component_id = str(output['id'])
+ component_property = str(output['property'])
+ callback_func_name = self.callback_map[target_id]['func'].__name__
+ self._validate_callback_output(namespace, component_type,
+ component_id, component_property,
+ callback_func_name,
+ args, output_value)
+
+ return self.callback_map[target_id]['callback'](output_value)
+
+ def _validate_callback_output(self, namespace, component_type,
+ component_id, component_property,
+ callback_func_name, args, value):
+ module = sys.modules[namespace]
+ component = getattr(module, component_type)
+ # pylint: disable=protected-access
+ validator = DashValidator({
+ component_property: component._schema.get(component_property, {})
+ })
+ valid = validator.validate({component_property: value})
+ if not valid:
+ error_message = dedent("""\
+
+ A Dash Callback produced an invalid value!
+
+ Dash tried to update the `{component_property}` prop of the
+ `{component_name}` with id `{component_id}` by calling the
+ `{callback_func_name}` function with `{args}` as arguments.
+
+ This function call returned `{value}`, which did not pass
+ validation tests for the `{component_name}` component.
+
+ The expected schema for the `{component_property}` prop of the
+ `{component_name}` component is:
+
+ ***************************************************************
+ {component_schema}
+ ***************************************************************
+
+ The errors in validation are as follows:
+
+ """).format(
+ component_property=component_property,
+ component_name=component.__name__,
+ component_id=component_id,
+ callback_func_name=callback_func_name,
+ args='({})'.format(", ".join(map(repr, args))),
+ value=value,
+ component_schema=pprint.pformat(
+ component._schema[component_property]
+ )
+ )
+
+ error_message = generate_validation_error_message(
+ validator.errors,
+ 0,
+ error_message
+ ) + dedent("""
+ You can turn off these validation exceptions by setting
+ `app.config.suppress_validation_exceptions=True`
+ """)
+
+ raise exceptions.CallbackOutputValidationError(error_message)
+ # Must also validate initialization of newly created components
+ if component_property == 'children':
+ if isinstance(value, Component):
+ value.validate()
+ for component in value.traverse():
+ if isinstance(component, Component):
+ component.validate()
 
  def _validate_layout(self):
  if self.layout is None:
@@ -932,6 +1024,11 @@ def _validate_layout(self):
 
  component_ids = {layout_id} if layout_id else set()
  for component in to_validate.traverse():
+ if (
+ not self.config.suppress_validation_exceptions and
+ isinstance(component, Component)
+ ):
+ component.validate()
  component_id = getattr(component, 'id', None)
  if component_id and component_id in component_ids:
  raise exceptions.DuplicateIdError(
@@ -1057,5 +1154,9 @@ def run_server(self,
  :return:
  """
  debug = self.enable_dev_tools(debug, dev_tools_serve_dev_bundles)
+ if not debug:
+ # Do not throw debugging exceptions in production.
+ self.config.suppress_validation_exceptions = True
+ self.config.suppress_callback_exceptions = True
  self.server.run(port=port, debug=debug,
  **flask_run_options)

.circleci/config.yml

@@ -49,6 +49,7 @@ jobs:
  python --version
  python -m unittest tests.development.test_base_component
  python -m unittest tests.development.test_component_loader
+ python -m unittest tests.development.test_component_validation
  python -m unittest tests.test_integration
  python -m unittest tests.test_resources
  python -m unittest tests.test_configs

.circleci/requirements/dev-requirements-py37.txt

@@ -9,8 +9,11 @@ mock
 tox
 tox-pyenv
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==2.1.1
 astroid==2.0.4
+Cerberus==1.2

.circleci/requirements/dev-requirements.txt

@@ -10,7 +10,10 @@ tox
 tox-pyenv
 mock
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==1.9.2
+Cerberus==1.2

.pylintrc37

@@ -63,6 +63,7 @@ confidence=
 disable=invalid-name,
  missing-docstring,
  print-statement,
+ too-many-lines,
  parameter-unpacking,
  unpacking-in-except,
  old-raise-syntax,

dash/dash.py

@@ -5,11 +5,13 @@
 import collections
 import importlib
 import json
+import pprint
 import pkgutil
 import warnings
 import re
 
 from functools import wraps
+from textwrap import dedent
 
 import plotly
 import dash_renderer
@@ -20,6 +22,8 @@
 from .dependencies import Event, Input, Output, State
 from .resources import Scripts, Css
 from .development.base_component import Component
+from .development.validator import (DashValidator,
+ generate_validation_error_message)
 from . import exceptions
 from ._utils import AttributeDict as _AttributeDict
 from ._utils import interpolate_str as _interpolate
@@ -84,6 +88,7 @@ def __init__(
  external_scripts=None,
  external_stylesheets=None,
  suppress_callback_exceptions=None,
+ suppress_validation_exceptions=None,
  components_cache_max_age=None,
  **kwargs):
 
@@ -126,6 +131,10 @@ def __init__(
  'suppress_callback_exceptions',
  suppress_callback_exceptions, env_configs, False
  ),
+ 'suppress_validation_exceptions': _configs.get_config(
+ 'suppress_validation_exceptions',
+ suppress_validation_exceptions, env_configs, False
+ ),
  'routes_pathname_prefix': routes_pathname_prefix,
  'requests_pathname_prefix': requests_pathname_prefix,
  'include_assets_files': _configs.get_config(
@@ -168,6 +177,7 @@ def _handle_error(error):
  self.assets_ignore = assets_ignore
 
  self.registered_paths = {}
+ self.namespaces = {}
 
  # urls
  self.routes = []
@@ -256,7 +266,6 @@ def layout(self, value):
  'a dash component.')
 
  self._layout = value
-
  layout_value = self._layout_value()
  # pylint: disable=protected-access
  self.css._update_layout(layout_value)
@@ -575,7 +584,7 @@ def react(self, *args, **kwargs):
  'Use `callback` instead. `callback` has a new syntax too, '
  'so make sure to call `help(app.callback)` to learn more.')
 
- def _validate_callback(self, output, inputs, state, events):
+ def _validate_callback_definition(self, output, inputs, state, events):
  # pylint: disable=too-many-branches
  layout = self._cached_layout or self._layout_value()
 
@@ -713,7 +722,7 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
- def _validate_callback_output(self, output_value, output):
+ def _debug_callback_serialization_error(self, output_value, output):
  valid = [str, dict, int, float, type(None), Component]
 
  def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
@@ -831,7 +840,7 @@ def _validate_value(val, index=None):
  # relationships
  # pylint: disable=dangerous-default-value
  def callback(self, output, inputs=[], state=[], events=[]):
- self._validate_callback(output, inputs, state, events)
+ self._validate_callback_definition(output, inputs, state, events)
 
  callback_id = '{}.{}'.format(
  output.component_id, output.component_property
@@ -853,13 +862,11 @@ def callback(self, output, inputs=[], state=[], events=[]):
 
  def wrap_func(func):
  @wraps(func)
- def add_context(*args, **kwargs):
-
- output_value = func(*args, **kwargs)
+ def add_context(validated_output):
  response = {
  'response': {
  'props': {
- output.component_property: output_value
+ output.component_property: validated_output
  }
  }
  }
@@ -870,7 +877,10 @@ def add_context(*args, **kwargs):
  cls=plotly.utils.PlotlyJSONEncoder
  )
  except TypeError:
- self._validate_callback_output(output_value, output)
+ self._debug_callback_serialization_error(
+ validated_output,
+ output
+ )
  raise exceptions.InvalidCallbackReturnValue('''
  The callback for property `{property:s}`
  of component `{id:s}` returned a value
@@ -887,6 +897,7 @@ def add_context(*args, **kwargs):
  mimetype='application/json'
  )
 
+ self.callback_map[callback_id]['func'] = func
  self.callback_map[callback_id]['callback'] = add_context
 
  return add_context
@@ -915,7 +926,88 @@ def dispatch(self):
  c['id'] == component_registration['id']
  ][0])
 
- return self.callback_map[target_id]['callback'](*args)
+ output_value = self.callback_map[target_id]['func'](*args)
+
+ # Only validate if we get required information from renderer
+ # and validation is not turned off by user
+ if (
+ (not self.config.suppress_validation_exceptions) and
+ 'namespace' in output and
+ 'type' in output
+ ):
+ # Python2.7 might make these keys and values unicode
+ namespace = str(output['namespace'])
+ component_type = str(output['type'])
+ component_id = str(output['id'])
+ component_property = str(output['property'])
+ callback_func_name = self.callback_map[target_id]['func'].__name__
+ self._validate_callback_output(namespace, component_type,
+ component_id, component_property,
+ callback_func_name,
+ args, output_value)
+
+ return self.callback_map[target_id]['callback'](output_value)
+
+ def _validate_callback_output(self, namespace, component_type,
+ component_id, component_property,
+ callback_func_name, args, value):
+ module = sys.modules[namespace]
+ component = getattr(module, component_type)
+ # pylint: disable=protected-access
+ validator = DashValidator({
+ component_property: component._schema.get(component_property, {})
+ })
+ valid = validator.validate({component_property: value})
+ if not valid:
+ error_message = dedent("""\
+
+ A Dash Callback produced an invalid value!
+
+ Dash tried to update the `{component_property}` prop of the
+ `{component_name}` with id `{component_id}` by calling the
+ `{callback_func_name}` function with `{args}` as arguments.
+
+ This function call returned `{value}`, which did not pass
+ validation tests for the `{component_name}` component.
+
+ The expected schema for the `{component_property}` prop of the
+ `{component_name}` component is:
+
+ ***************************************************************
+ {component_schema}
+ ***************************************************************
+
+ The errors in validation are as follows:
+
+ """).format(
+ component_property=component_property,
+ component_name=component.__name__,
+ component_id=component_id,
+ callback_func_name=callback_func_name,
+ args='({})'.format(", ".join(map(repr, args))),
+ value=value,
+ component_schema=pprint.pformat(
+ component._schema[component_property]
+ )
+ )
+
+ error_message = generate_validation_error_message(
+ validator.errors,
+ 0,
+ error_message
+ ) + dedent("""
+ You can turn off these validation exceptions by setting
+ `app.config.suppress_validation_exceptions=True`
+ """)
+
+ raise exceptions.CallbackOutputValidationError(error_message)
+ # Must also validate initialization of newly created components
+ if component_property == 'children':
+ if isinstance(value, Component):
+ value.validate()
+ for component in value.traverse():
+ if isinstance(component, Component):
+ component.validate()
 
  def _validate_layout(self):
  if self.layout is None:
@@ -932,6 +1024,11 @@ def _validate_layout(self):
 
  component_ids = {layout_id} if layout_id else set()
  for component in to_validate.traverse():
+ if (
+ not self.config.suppress_validation_exceptions and
+ isinstance(component, Component)
+ ):
+ component.validate()
  component_id = getattr(component, 'id', None)
  if component_id and component_id in component_ids:
  raise exceptions.DuplicateIdError(
@@ -1057,5 +1154,9 @@ def run_server(self,
  :return:
  """
  debug = self.enable_dev_tools(debug, dev_tools_serve_dev_bundles)
+ if not debug:
+ # Do not throw debugging exceptions in production.
+ self.config.suppress_validation_exceptions = True
+ self.config.suppress_callback_exceptions = True
  self.server.run(port=port, debug=debug,
  **flask_run_options)

.circleci/config.yml

@@ -49,6 +49,7 @@ jobs:
  python --version
  python -m unittest tests.development.test_base_component
  python -m unittest tests.development.test_component_loader
+ python -m unittest tests.development.test_component_validation
  python -m unittest tests.test_integration
  python -m unittest tests.test_resources
  python -m unittest tests.test_configs

.circleci/requirements/dev-requirements-py37.txt

@@ -9,8 +9,11 @@ mock
 tox
 tox-pyenv
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==2.1.1
 astroid==2.0.4
+Cerberus==1.2

.circleci/requirements/dev-requirements.txt

@@ -10,7 +10,10 @@ tox
 tox-pyenv
 mock
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==1.9.2
+Cerberus==1.2

.pylintrc37

@@ -63,6 +63,7 @@ confidence=
 disable=invalid-name,
  missing-docstring,
  print-statement,
+ too-many-lines,
  parameter-unpacking,
  unpacking-in-except,
  old-raise-syntax,

dash/dash.py

@@ -5,11 +5,13 @@
 import collections
 import importlib
 import json
+import pprint
 import pkgutil
 import warnings
 import re
 
 from functools import wraps
+from textwrap import dedent
 
 import plotly
 import dash_renderer
@@ -20,6 +22,8 @@
 from .dependencies import Event, Input, Output, State
 from .resources import Scripts, Css
 from .development.base_component import Component
+from .development.validator import (DashValidator,
+ generate_validation_error_message)
 from . import exceptions
 from ._utils import AttributeDict as _AttributeDict
 from ._utils import interpolate_str as _interpolate
@@ -84,6 +88,7 @@ def __init__(
  external_scripts=None,
  external_stylesheets=None,
  suppress_callback_exceptions=None,
+ suppress_validation_exceptions=None,
  components_cache_max_age=None,
  **kwargs):
 
@@ -126,6 +131,10 @@ def __init__(
  'suppress_callback_exceptions',
  suppress_callback_exceptions, env_configs, False
  ),
+ 'suppress_validation_exceptions': _configs.get_config(
+ 'suppress_validation_exceptions',
+ suppress_validation_exceptions, env_configs, False
+ ),
  'routes_pathname_prefix': routes_pathname_prefix,
  'requests_pathname_prefix': requests_pathname_prefix,
  'include_assets_files': _configs.get_config(
@@ -168,6 +177,7 @@ def _handle_error(error):
  self.assets_ignore = assets_ignore
 
  self.registered_paths = {}
+ self.namespaces = {}
 
  # urls
  self.routes = []
@@ -256,7 +266,6 @@ def layout(self, value):
  'a dash component.')
 
  self._layout = value
-
  layout_value = self._layout_value()
  # pylint: disable=protected-access
  self.css._update_layout(layout_value)
@@ -575,7 +584,7 @@ def react(self, *args, **kwargs):
  'Use `callback` instead. `callback` has a new syntax too, '
  'so make sure to call `help(app.callback)` to learn more.')
 
- def _validate_callback(self, output, inputs, state, events):
+ def _validate_callback_definition(self, output, inputs, state, events):
  # pylint: disable=too-many-branches
  layout = self._cached_layout or self._layout_value()
 
@@ -713,7 +722,7 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
- def _validate_callback_output(self, output_value, output):
+ def _debug_callback_serialization_error(self, output_value, output):
  valid = [str, dict, int, float, type(None), Component]
 
  def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
@@ -831,7 +840,7 @@ def _validate_value(val, index=None):
  # relationships
  # pylint: disable=dangerous-default-value
  def callback(self, output, inputs=[], state=[], events=[]):
- self._validate_callback(output, inputs, state, events)
+ self._validate_callback_definition(output, inputs, state, events)
 
  callback_id = '{}.{}'.format(
  output.component_id, output.component_property
@@ -853,13 +862,11 @@ def callback(self, output, inputs=[], state=[], events=[]):
 
  def wrap_func(func):
  @wraps(func)
- def add_context(*args, **kwargs):
-
- output_value = func(*args, **kwargs)
+ def add_context(validated_output):
  response = {
  'response': {
  'props': {
- output.component_property: output_value
+ output.component_property: validated_output
  }
  }
  }
@@ -870,7 +877,10 @@ def add_context(*args, **kwargs):
  cls=plotly.utils.PlotlyJSONEncoder
  )
  except TypeError:
- self._validate_callback_output(output_value, output)
+ self._debug_callback_serialization_error(
+ validated_output,
+ output
+ )
  raise exceptions.InvalidCallbackReturnValue('''
  The callback for property `{property:s}`
  of component `{id:s}` returned a value
@@ -887,6 +897,7 @@ def add_context(*args, **kwargs):
  mimetype='application/json'
  )
 
+ self.callback_map[callback_id]['func'] = func
  self.callback_map[callback_id]['callback'] = add_context
 
  return add_context
@@ -915,7 +926,88 @@ def dispatch(self):
  c['id'] == component_registration['id']
  ][0])
 
- return self.callback_map[target_id]['callback'](*args)
+ output_value = self.callback_map[target_id]['func'](*args)
+
+ # Only validate if we get required information from renderer
+ # and validation is not turned off by user
+ if (
+ (not self.config.suppress_validation_exceptions) and
+ 'namespace' in output and
+ 'type' in output
+ ):
+ # Python2.7 might make these keys and values unicode
+ namespace = str(output['namespace'])
+ component_type = str(output['type'])
+ component_id = str(output['id'])
+ component_property = str(output['property'])
+ callback_func_name = self.callback_map[target_id]['func'].__name__
+ self._validate_callback_output(namespace, component_type,
+ component_id, component_property,
+ callback_func_name,
+ args, output_value)
+
+ return self.callback_map[target_id]['callback'](output_value)
+
+ def _validate_callback_output(self, namespace, component_type,
+ component_id, component_property,
+ callback_func_name, args, value):
+ module = sys.modules[namespace]
+ component = getattr(module, component_type)
+ # pylint: disable=protected-access
+ validator = DashValidator({
+ component_property: component._schema.get(component_property, {})
+ })
+ valid = validator.validate({component_property: value})
+ if not valid:
+ error_message = dedent("""\
+
+ A Dash Callback produced an invalid value!
+
+ Dash tried to update the `{component_property}` prop of the
+ `{component_name}` with id `{component_id}` by calling the
+ `{callback_func_name}` function with `{args}` as arguments.
+
+ This function call returned `{value}`, which did not pass
+ validation tests for the `{component_name}` component.
+
+ The expected schema for the `{component_property}` prop of the
+ `{component_name}` component is:
+
+ ***************************************************************
+ {component_schema}
+ ***************************************************************
+
+ The errors in validation are as follows:
+
+ """).format(
+ component_property=component_property,
+ component_name=component.__name__,
+ component_id=component_id,
+ callback_func_name=callback_func_name,
+ args='({})'.format(", ".join(map(repr, args))),
+ value=value,
+ component_schema=pprint.pformat(
+ component._schema[component_property]
+ )
+ )
+
+ error_message = generate_validation_error_message(
+ validator.errors,
+ 0,
+ error_message
+ ) + dedent("""
+ You can turn off these validation exceptions by setting
+ `app.config.suppress_validation_exceptions=True`
+ """)
+
+ raise exceptions.CallbackOutputValidationError(error_message)
+ # Must also validate initialization of newly created components
+ if component_property == 'children':
+ if isinstance(value, Component):
+ value.validate()
+ for component in value.traverse():
+ if isinstance(component, Component):
+ component.validate()
 
  def _validate_layout(self):
  if self.layout is None:
@@ -932,6 +1024,11 @@ def _validate_layout(self):
 
  component_ids = {layout_id} if layout_id else set()
  for component in to_validate.traverse():
+ if (
+ not self.config.suppress_validation_exceptions and
+ isinstance(component, Component)
+ ):
+ component.validate()
  component_id = getattr(component, 'id', None)
  if component_id and component_id in component_ids:
  raise exceptions.DuplicateIdError(
@@ -1057,5 +1154,9 @@ def run_server(self,
  :return:
  """
  debug = self.enable_dev_tools(debug, dev_tools_serve_dev_bundles)
+ if not debug:
+ # Do not throw debugging exceptions in production.
+ self.config.suppress_validation_exceptions = True
+ self.config.suppress_callback_exceptions = True
  self.server.run(port=port, debug=debug,
  **flask_run_options)

.circleci/config.yml

@@ -49,6 +49,7 @@ jobs:
  python --version
  python -m unittest tests.development.test_base_component
  python -m unittest tests.development.test_component_loader
+ python -m unittest tests.development.test_component_validation
  python -m unittest tests.test_integration
  python -m unittest tests.test_resources
  python -m unittest tests.test_configs

.circleci/requirements/dev-requirements-py37.txt

@@ -9,8 +9,11 @@ mock
 tox
 tox-pyenv
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==2.1.1
 astroid==2.0.4
+Cerberus==1.2

.circleci/requirements/dev-requirements.txt

@@ -10,7 +10,10 @@ tox
 tox-pyenv
 mock
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==1.9.2
+Cerberus==1.2

.pylintrc37

@@ -63,6 +63,7 @@ confidence=
 disable=invalid-name,
  missing-docstring,
  print-statement,
+ too-many-lines,
  parameter-unpacking,
  unpacking-in-except,
  old-raise-syntax,

dash/dash.py

@@ -5,11 +5,13 @@
 import collections
 import importlib
 import json
+import pprint
 import pkgutil
 import warnings
 import re
 
 from functools import wraps
+from textwrap import dedent
 
 import plotly
 import dash_renderer
@@ -20,6 +22,8 @@
 from .dependencies import Event, Input, Output, State
 from .resources import Scripts, Css
 from .development.base_component import Component
+from .development.validator import (DashValidator,
+ generate_validation_error_message)
 from . import exceptions
 from ._utils import AttributeDict as _AttributeDict
 from ._utils import interpolate_str as _interpolate
@@ -84,6 +88,7 @@ def __init__(
  external_scripts=None,
  external_stylesheets=None,
  suppress_callback_exceptions=None,
+ suppress_validation_exceptions=None,
  components_cache_max_age=None,
  **kwargs):
 
@@ -126,6 +131,10 @@ def __init__(
  'suppress_callback_exceptions',
  suppress_callback_exceptions, env_configs, False
  ),
+ 'suppress_validation_exceptions': _configs.get_config(
+ 'suppress_validation_exceptions',
+ suppress_validation_exceptions, env_configs, False
+ ),
  'routes_pathname_prefix': routes_pathname_prefix,
  'requests_pathname_prefix': requests_pathname_prefix,
  'include_assets_files': _configs.get_config(
@@ -168,6 +177,7 @@ def _handle_error(error):
  self.assets_ignore = assets_ignore
 
  self.registered_paths = {}
+ self.namespaces = {}
 
  # urls
  self.routes = []
@@ -256,7 +266,6 @@ def layout(self, value):
  'a dash component.')
 
  self._layout = value
-
  layout_value = self._layout_value()
  # pylint: disable=protected-access
  self.css._update_layout(layout_value)
@@ -575,7 +584,7 @@ def react(self, *args, **kwargs):
  'Use `callback` instead. `callback` has a new syntax too, '
  'so make sure to call `help(app.callback)` to learn more.')
 
- def _validate_callback(self, output, inputs, state, events):
+ def _validate_callback_definition(self, output, inputs, state, events):
  # pylint: disable=too-many-branches
  layout = self._cached_layout or self._layout_value()
 
@@ -713,7 +722,7 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
- def _validate_callback_output(self, output_value, output):
+ def _debug_callback_serialization_error(self, output_value, output):
  valid = [str, dict, int, float, type(None), Component]
 
  def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
@@ -831,7 +840,7 @@ def _validate_value(val, index=None):
  # relationships
  # pylint: disable=dangerous-default-value
  def callback(self, output, inputs=[], state=[], events=[]):
- self._validate_callback(output, inputs, state, events)
+ self._validate_callback_definition(output, inputs, state, events)
 
  callback_id = '{}.{}'.format(
  output.component_id, output.component_property
@@ -853,13 +862,11 @@ def callback(self, output, inputs=[], state=[], events=[]):
 
  def wrap_func(func):
  @wraps(func)
- def add_context(*args, **kwargs):
-
- output_value = func(*args, **kwargs)
+ def add_context(validated_output):
  response = {
  'response': {
  'props': {
- output.component_property: output_value
+ output.component_property: validated_output
  }
  }
  }
@@ -870,7 +877,10 @@ def add_context(*args, **kwargs):
  cls=plotly.utils.PlotlyJSONEncoder
  )
  except TypeError:
- self._validate_callback_output(output_value, output)
+ self._debug_callback_serialization_error(
+ validated_output,
+ output
+ )
  raise exceptions.InvalidCallbackReturnValue('''
  The callback for property `{property:s}`
  of component `{id:s}` returned a value
@@ -887,6 +897,7 @@ def add_context(*args, **kwargs):
  mimetype='application/json'
  )
 
+ self.callback_map[callback_id]['func'] = func
  self.callback_map[callback_id]['callback'] = add_context
 
  return add_context
@@ -915,7 +926,88 @@ def dispatch(self):
  c['id'] == component_registration['id']
  ][0])
 
- return self.callback_map[target_id]['callback'](*args)
+ output_value = self.callback_map[target_id]['func'](*args)
+
+ # Only validate if we get required information from renderer
+ # and validation is not turned off by user
+ if (
+ (not self.config.suppress_validation_exceptions) and
+ 'namespace' in output and
+ 'type' in output
+ ):
+ # Python2.7 might make these keys and values unicode
+ namespace = str(output['namespace'])
+ component_type = str(output['type'])
+ component_id = str(output['id'])
+ component_property = str(output['property'])
+ callback_func_name = self.callback_map[target_id]['func'].__name__
+ self._validate_callback_output(namespace, component_type,
+ component_id, component_property,
+ callback_func_name,
+ args, output_value)
+
+ return self.callback_map[target_id]['callback'](output_value)
+
+ def _validate_callback_output(self, namespace, component_type,
+ component_id, component_property,
+ callback_func_name, args, value):
+ module = sys.modules[namespace]
+ component = getattr(module, component_type)
+ # pylint: disable=protected-access
+ validator = DashValidator({
+ component_property: component._schema.get(component_property, {})
+ })
+ valid = validator.validate({component_property: value})
+ if not valid:
+ error_message = dedent("""\
+
+ A Dash Callback produced an invalid value!
+
+ Dash tried to update the `{component_property}` prop of the
+ `{component_name}` with id `{component_id}` by calling the
+ `{callback_func_name}` function with `{args}` as arguments.
+
+ This function call returned `{value}`, which did not pass
+ validation tests for the `{component_name}` component.
+
+ The expected schema for the `{component_property}` prop of the
+ `{component_name}` component is:
+
+ ***************************************************************
+ {component_schema}
+ ***************************************************************
+
+ The errors in validation are as follows:
+
+ """).format(
+ component_property=component_property,
+ component_name=component.__name__,
+ component_id=component_id,
+ callback_func_name=callback_func_name,
+ args='({})'.format(", ".join(map(repr, args))),
+ value=value,
+ component_schema=pprint.pformat(
+ component._schema[component_property]
+ )
+ )
+
+ error_message = generate_validation_error_message(
+ validator.errors,
+ 0,
+ error_message
+ ) + dedent("""
+ You can turn off these validation exceptions by setting
+ `app.config.suppress_validation_exceptions=True`
+ """)
+
+ raise exceptions.CallbackOutputValidationError(error_message)
+ # Must also validate initialization of newly created components
+ if component_property == 'children':
+ if isinstance(value, Component):
+ value.validate()
+ for component in value.traverse():
+ if isinstance(component, Component):
+ component.validate()
 
  def _validate_layout(self):
  if self.layout is None:
@@ -932,6 +1024,11 @@ def _validate_layout(self):
 
  component_ids = {layout_id} if layout_id else set()
  for component in to_validate.traverse():
+ if (
+ not self.config.suppress_validation_exceptions and
+ isinstance(component, Component)
+ ):
+ component.validate()
  component_id = getattr(component, 'id', None)
  if component_id and component_id in component_ids:
  raise exceptions.DuplicateIdError(
@@ -1057,5 +1154,9 @@ def run_server(self,
  :return:
  """
  debug = self.enable_dev_tools(debug, dev_tools_serve_dev_bundles)
+ if not debug:
+ # Do not throw debugging exceptions in production.
+ self.config.suppress_validation_exceptions = True
+ self.config.suppress_callback_exceptions = True
  self.server.run(port=port, debug=debug,
  **flask_run_options)

.circleci/config.yml

@@ -49,6 +49,7 @@ jobs:
  python --version
  python -m unittest tests.development.test_base_component
  python -m unittest tests.development.test_component_loader
+ python -m unittest tests.development.test_component_validation
  python -m unittest tests.test_integration
  python -m unittest tests.test_resources
  python -m unittest tests.test_configs

.circleci/requirements/dev-requirements-py37.txt

@@ -9,8 +9,11 @@ mock
 tox
 tox-pyenv
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==2.1.1
 astroid==2.0.4
+Cerberus==1.2

.circleci/requirements/dev-requirements.txt

@@ -10,7 +10,10 @@ tox
 tox-pyenv
 mock
 six
+numpy
+pandas
 plotly>=2.0.8
 requests[security]
 flake8
 pylint==1.9.2
+Cerberus==1.2

.pylintrc37

@@ -63,6 +63,7 @@ confidence=
 disable=invalid-name,
  missing-docstring,
  print-statement,
+ too-many-lines,
  parameter-unpacking,
  unpacking-in-except,
  old-raise-syntax,

dash/dash.py

@@ -5,11 +5,13 @@
 import collections
 import importlib
 import json
+import pprint
 import pkgutil
 import warnings
 import re
 
 from functools import wraps
+from textwrap import dedent
 
 import plotly
 import dash_renderer
@@ -20,6 +22,8 @@
 from .dependencies import Event, Input, Output, State
 from .resources import Scripts, Css
 from .development.base_component import Component
+from .development.validator import (DashValidator,
+ generate_validation_error_message)
 from . import exceptions
 from ._utils import AttributeDict as _AttributeDict
 from ._utils import interpolate_str as _interpolate
@@ -84,6 +88,7 @@ def __init__(
  external_scripts=None,
  external_stylesheets=None,
  suppress_callback_exceptions=None,
+ suppress_validation_exceptions=None,
  components_cache_max_age=None,
  **kwargs):
 
@@ -126,6 +131,10 @@ def __init__(
  'suppress_callback_exceptions',
  suppress_callback_exceptions, env_configs, False
  ),
+ 'suppress_validation_exceptions': _configs.get_config(
+ 'suppress_validation_exceptions',
+ suppress_validation_exceptions, env_configs, False
+ ),
  'routes_pathname_prefix': routes_pathname_prefix,
  'requests_pathname_prefix': requests_pathname_prefix,
  'include_assets_files': _configs.get_config(
@@ -168,6 +177,7 @@ def _handle_error(error):
  self.assets_ignore = assets_ignore
 
  self.registered_paths = {}
+ self.namespaces = {}
 
  # urls
  self.routes = []
@@ -256,7 +266,6 @@ def layout(self, value):
  'a dash component.')
 
  self._layout = value
-
  layout_value = self._layout_value()
  # pylint: disable=protected-access
  self.css._update_layout(layout_value)
@@ -575,7 +584,7 @@ def react(self, *args, **kwargs):
  'Use `callback` instead. `callback` has a new syntax too, '
  'so make sure to call `help(app.callback)` to learn more.')
 
- def _validate_callback(self, output, inputs, state, events):
+ def _validate_callback_definition(self, output, inputs, state, events):
  # pylint: disable=too-many-branches
  layout = self._cached_layout or self._layout_value()
 
@@ -713,7 +722,7 @@ def _validate_callback(self, output, inputs, state, events):
  output.component_id,
  output.component_property).replace(' ', ''))
 
- def _validate_callback_output(self, output_value, output):
+ def _debug_callback_serialization_error(self, output_value, output):
  valid = [str, dict, int, float, type(None), Component]
 
  def _raise_invalid(bad_val, outer_val, bad_type, path, index=None,
@@ -831,7 +840,7 @@ def _validate_value(val, index=None):
  # relationships
  # pylint: disable=dangerous-default-value
  def callback(self, output, inputs=[], state=[], events=[]):
- self._validate_callback(output, inputs, state, events)
+ self._validate_callback_definition(output, inputs, state, events)
 
  callback_id = '{}.{}'.format(
  output.component_id, output.component_property
@@ -853,13 +862,11 @@ def callback(self, output, inputs=[], state=[], events=[]):
 
  def wrap_func(func):
  @wraps(func)
- def add_context(*args, **kwargs):
-
- output_value = func(*args, **kwargs)
+ def add_context(validated_output):
  response = {
  'response': {
  'props': {
- output.component_property: output_value
+ output.component_property: validated_output
  }
  }
  }
@@ -870,7 +877,10 @@ def add_context(*args, **kwargs):
  cls=plotly.utils.PlotlyJSONEncoder
  )
  except TypeError:
- self._validate_callback_output(output_value, output)
+ self._debug_callback_serialization_error(
+ validated_output,
+ output
+ )
  raise exceptions.InvalidCallbackReturnValue('''
  The callback for property `{property:s}`
  of component `{id:s}` returned a value
@@ -887,6 +897,7 @@ def add_context(*args, **kwargs):
  mimetype='application/json'
  )
 
+ self.callback_map[callback_id]['func'] = func
  self.callback_map[callback_id]['callback'] = add_context
 
  return add_context
@@ -915,7 +926,88 @@ def dispatch(self):
  c['id'] == component_registration['id']
  ][0])
 
- return self.callback_map[target_id]['callback'](*args)
+ output_value = self.callback_map[target_id]['func'](*args)
+
+ # Only validate if we get required information from renderer
+ # and validation is not turned off by user
+ if (
+ (not self.config.suppress_validation_exceptions) and
+ 'namespace' in output and
+ 'type' in output
+ ):
+ # Python2.7 might make these keys and values unicode
+ namespace = str(output['namespace'])
+ component_type = str(output['type'])
+ component_id = str(output['id'])
+ component_property = str(output['property'])
+ callback_func_name = self.callback_map[target_id]['func'].__name__
+ self._validate_callback_output(namespace, component_type,
+ component_id, component_property,
+ callback_func_name,
+ args, output_value)
+
+ return self.callback_map[target_id]['callback'](output_value)
+
+ def _validate_callback_output(self, namespace, component_type,
+ component_id, component_property,
+ callback_func_name, args, value):
+ module = sys.modules[namespace]
+ component = getattr(module, component_type)
+ # pylint: disable=protected-access
+ validator = DashValidator({
+ component_property: component._schema.get(component_property, {})
+ })
+ valid = validator.validate({component_property: value})
+ if not valid:
+ error_message = dedent("""\
+
+ A Dash Callback produced an invalid value!
+
+ Dash tried to update the `{component_property}` prop of the
+ `{component_name}` with id `{component_id}` by calling the
+ `{callback_func_name}` function with `{args}` as arguments.
+
+ This function call returned `{value}`, which did not pass
+ validation tests for the `{component_name}` component.
+
+ The expected schema for the `{component_property}` prop of the
+ `{component_name}` component is:
+
+ ***************************************************************
+ {component_schema}
+ ***************************************************************
+
+ The errors in validation are as follows:
+
+ """).format(
+ component_property=component_property,
+ component_name=component.__name__,
+ component_id=component_id,
+ callback_func_name=callback_func_name,
+ args='({})'.format(", ".join(map(repr, args))),
+ value=value,
+ component_schema=pprint.pformat(
+ component._schema[component_property]
+ )
+ )
+
+ error_message = generate_validation_error_message(
+ validator.errors,
+ 0,
+ error_message
+ ) + dedent("""
+ You can turn off these validation exceptions by setting
+ `app.config.suppress_validation_exceptions=True`
+ """)
+
+ raise exceptions.CallbackOutputValidationError(error_message)
+ # Must also validate initialization of newly created components
+ if component_property == 'children':
+ if isinstance(value, Component):
+ value.validate()
+ for component in value.traverse():
+ if isinstance(component, Component):
+ component.validate()
 
  def _validate_layout(self):
  if self.layout is None:
@@ -932,6 +1024,11 @@ def _validate_layout(self):
 
  component_ids = {layout_id} if layout_id else set()
  for component in to_validate.traverse():
+ if (
+ not self.config.suppress_validation_exceptions and
+ isinstance(component, Component)
+ ):
+ component.validate()
  component_id = getattr(component, 'id', None)
  if component_id and component_id in component_ids:
  raise exceptions.DuplicateIdError(
@@ -1057,5 +1154,9 @@ def run_server(self,
  :return:
  """
  debug = self.enable_dev_tools(debug, dev_tools_serve_dev_bundles)
+ if not debug:
+ # Do not throw debugging exceptions in production.
+ self.config.suppress_validation_exceptions = True
+ self.config.suppress_callback_exceptions = True
  self.server.run(port=port, debug=debug,
  **flask_run_options)